Search

A hybrid photothermal catalytic system, which combines both the photochemical (light) and thermal (heat) activation pathways over a bifunctional catalyst, has demonstrated remarkable levels of reaction activity and selectivity when compared with individual photocatalysis and thermocatalysis. However, the complex nature of the hybrid system, coupled with the synergy between photocatalysis and thermocatalysis, has made it challenging to understand (and thus manipulate) the role of individual stimuli (light/heat) and catalyst surface processes. In this perspective, a systematic classification for different (complicated) photothermal catalysis reaction systems is provided. We evaluate the singular catalytic characteristics of each category, together with the competence of light-heat dual activation in overcoming the well-defined limitations in photocatalysis and thermocatalysis, mainly in the scope of C1 chemistry. Notably, the interplay and cooperation among heat and/or light-induced effects can be engineered to greatly extend the capability of chemical transformation (i.e., product selectivity and reactivity) via the well-established photo-thermo cascade reaction. Finally, we provide critical insights into the catalyst development and reactor design for high-performance light-heat-coupled catalytic systems.

Bi2WO6/WO3heterojunction thin films with low or high interfacial contact between the Bi2WO6and WO3photocatalyst were employed as the photoanode for photoelectrochemical (PEC) reactions. By modulation of the transformation of WO3to Bi2WO6via a combined electrodeposition and hydrothermal reaction, a controlled degree of interfacial contact between Bi2WO6and WO3was achieved. An increase in the anodic photocurrent was observed from the PEC measurement, which was further supported by the conductive atomic force microscopy analysis under a low applied bias when the higher Bi2WO6/WO3interfacial contact photoelectrode was examined. Experiment results suggested that the improvement was ascribed to a lower density of surface trap of the photoelectrons that reduced the charge recombination rate within the bulk photocatalyst.

Hydrogen production through water electrolysis is a promising method to utilize renewable energy in the context of urgent need to phase out fossil fuels. Nickel–molybdenum (NiMo) electrodes are among the best performing non-noble metal-based electrodes for hydrogen evolution reaction in alkaline media (alkaline HER). Albeit exhibiting stable performance in electrolysis at a constant power supply (i.e., constant electrolysis), NiMo electrodes suffer from performance degradation in electrolysis at an intermittent power supply (i.e., intermittent electrolysis), which is emblematic of electrolysis powered directly by renewable energy (such as wind and solar power sources). Here we reveal that NiMo electrodes were oxidized by dissolved oxygen during power interruption, leading to vanishing of metallic Ni active sites and loss of conductivity in MoOxsubstrate. Based on the understanding of the degradation mechanism, chromium (Cr) coating was successfully applied as a protective layer to inhibit oxygen reduction reaction (ORR) and significantly enhance the stability of NiMo electrodes in intermittent electrolysis. Further, combining experimental and Molecular Dynamics (MD) simulations, we demonstrate that the Cr coating served as a physical barrier inhibiting diffusion of oxygen, while still allowing other species to pass through. Our work offers insights into electrode behavior in intermittent electrolysis, as well as provides Cr coating as a valid method and corresponding deep understanding of the factors for stability enhancement, paving the way for the successful application of lab-scale electrodes in industrial electrolysis powered directly by renewable energy.

The large-scale deployment of proton-exchange membrane water electrolyzers for high-throughput sustainable hydrogen production requires transition from precious noble metal anode electrocatalysts to low-cost earth-abundant materials. However, such materials are commonly insufficiently stable and/or catalytically inactive at low pH, and positive potentials required to maintain high rates of the anodic oxygen evolution reaction (OER). To address this, we explore the effects of a dielectric nanoscale-thin layer, constituted of amorphous TiO2, on the stability and electrocatalytic activity of nanostructured OER anodes based on low-cost Co3O4. We demonstrate a direct correlation between the OER performance and the thickness of the atomic layer deposited TiO2layers. An optimal TiO2layer thickness of 4.4 nm enhances the anode lifetime by a factor of ca. 3, achieving 80 h of continuous electrolysis at pH near zero, while preserving high OER catalytic activity of the bare Co3O4surface. Thinner and thicker TiO2layers decrease the stability and activity, respectively. This is attributed to the pitting of the TiO2layer at the optimal thickness, which allows for access to the catalytically active Co3O4surface while stabilizing it against corrosion. These insights provide directions for the engineering of active and stable composite earth-abundant materials for acidic water splitting for high-throughput hydrogen production.

Binary TiO2/SiO2oxides were synthesized viaflame spray pyrolysis as supports for a Pt catalyst. The effect of the mole ratio of the silica on the catalyst characteristics and catalytic performance for formic acid oxidation under dark (non-illuminated) conditions and following UV light pre-treatment was examined. As the TiO2 : SiO2ratio increased, the following was observed: (i) the specific surface area gradually decreased from ∼325 m2g−1to ∼50 m2g−1; (ii) the crystal structure was transformed from amorphous titania to crystalline anatase phase; (iii) the defect sites comprising Ti3+, E′ centres, and non-bridging oxygen hole centers (NBOHCs) were maximum at a TiO2 : SiO2ratio of 1 : 2 (Pt/1TiO2–2SiO2); and (iv) oxygen adsorbed on the Pt deposit surface (PtOads) was a maximum for Pt/1TiO2–2SiO2. The catalytic activity of Pt–TiO2/SiO2was strongly dependent on the TiO2/SiO2ratio and was further enhanced by hydrogenation and UV light pre-treatment. In line with the greatest presence of support-based defects and PtOadsspecies, the Pt/1TiO2–2SiO2catalyst exhibited the highest catalytic rate following UV light pre-treatment. The simultaneously boosted presence of PtOadsand defect sites (comprising Ti3+, E′ centers, and NBOHC) on the Pt–TiO2/SiO2catalysts following UV-light pre-treatment is proposed as the origin of the enhanced formic acid oxidation reaction.

Photoreforming is a promising alternative to water splitting for H2generation due to the favorable organic oxidation half-reaction and the potential to simultaneously produce solar fuel and value-added chemicals. Recently, carbon nitride has received significant attention as an inexpensive photocatalyst for the photoreforming process. However, the application of carbon nitride continues to be hampered by its poor photocatalytic performance. Herein, we report for the first time a synergistic modification of an in situphotodeposited Ni cocatalyst on carbon nitride viacyanamide functionalization and solid/liquid interfacial charge-induced activation using excess Ni2+ions. Synergism between the cyanamide functionalization and charge-induced activation by the excess Ni2+ions invokes enhanced activity, selectivity, and stability during ethanol photoreforming. A H2evolution rate of 2.32 mmol h–1g–1in conjunction with an acetaldehyde production rate of 2.54 mmol h–1g–1was attained for the Ni/NCN-CN. The H2evolution rate and elevated acetaldehyde selectivity (above 98%) remained consistent under prolonged light illumination. To understand the origin of the complementary promotional effects, the contributions of cyanamide groups and excess Ni2+ions to selective ethanol photoreforming are decoupled and systematically investigated. The cyanamide functionality on carbon nitride was found to promote hole scavenging for the ethanol oxidation reaction, thereby enabling effective electron transfer to the Ni cocatalyst for H2evolution. Concomitantly, excess Ni2+ions remaining in solution created a positively charged environment on the photocatalyst surface, which improved charge carrier utilization and ethanol adsorption. The work highlights the importance of both carbon nitride functionality and charge on the photocatalyst surface in developing a selective photocatalytic reforming system.

A fundamental understanding of basic driving forces and the role of light in photothermal CO2catalysis is covered. The progress of the catalyst development and corresponding material engineering strategies are summarized.

The emergence of three-dimensional (3D) printing promises a disruption in the design and on-demand fabrication of smart structures in applications ranging from functional devices to human organs. However, the scale at which 3D printing excels is within macro- and microlevels and principally lacks the spatial ordering of building blocks at nanolevels, which is vital for most multifunctional devices. Herein, we employ liquid crystal (LC) inks to bridge the gap between the nano- and microscales in a single-step 3D printing. The LC ink is prepared from mixtures of LCs of nanocellulose whiskers and large sheets of graphene oxide, which offers a highly ordered laminar organization not inherently present in the source materials. LC-mediated 3D printing imparts the fine-tuning required for the design freedom of architecturally layered systems at the nanoscale with intricate patterns within the 3D-printed constructs. This approach empowered the development of a high-performance humidity sensor composed of self-assembled lamellar organization of NC whiskers. We observed that the NC whiskers that are flat and parallel to each other in the laminar organization allow facile mass transport through the structure, demonstrating a significant improvement in the sensor performance. This work exemplifies how LC ink, implemented in a 3D printing process, can unlock the potential of individual constituents to allow macroscopic printing architectures with nanoscopic arrangements.

Titanate nanoribbons were prepared by hydrothermal treatment of neat TiO2P25 with 10 M NaOH at 200 °C. Hydrothermal aging times were varied to assist with understanding the transformation process while the impact of postsynthesis acid washing on nanoribbon formation kinetics was assessed. Nanoribbon evolution was observed to occur via the formation of intermediate amorphous titanate particles. The final nanoribbon product was found to comprise a layered titanate framework with sodium cations interspersed between the sheets. Acid washing served to exchange the Na+with H+to give H2Ti3O7. Moreover, acid washing accelerated nanoribbon formation, providing a well-defined (i.e., no amorphous particles) nanoribbon sample after 15 h compared to 40 h when acid washing was not used. The difference in formation rates was attributed to interlayer formation of the intermediates in the hydrogen bond array (i.e., Ti−O−H) during H2Ti3O7being faster than intermediate formation in the sodium bond array (i.e., Ti−O−Na). Acid washing of the nanoribbon samples after extended hydrothermal synthesis times (>24 h) led to fragmenting of the structure.

As a widely used material, titanium is highly sought after due to its significant corrosion resistance properties resulting from the self-passivating natural oxide layer. Hydrothermal etching is a promising and scalable treatment technique for synthesizing surface nanostructures at high and low temperatures with new mesoscopic properties. However, the corrosive behavior of hydrothermally etched titanium remains unknown, posing a limitation on its industrial translation. Here, the impact of hydrothermal conditions on the corrosive properties of titanium is examined for three industrially relevant titanium alloys at high (150 °C) and low (75 °C) synthesis temperatures. Using a KOH etchant, nanotextured surfaces were fabricated on all titanium surfaces, forming a mixed titania and tetra-titanate (K2Ti4O9·nH2O) crystal structure. Subsurface analysis revealed that the oxide layer was significantly thickened (>1 μm), with total coverage of the bulk metal achieved for all low-temperature specimens. Electrochemical potentiodynamic evaluation of the nanosurfaces indicated the increased surface area produced an increased corrosion current, confirming the sustained resistance of the fabricated nanosurface. Long-term immersion in fluoridated artificial saliva highlighted the increased resistance of hydrothermal surfaces to degradation and release of titanium, aluminum, and vanadium ions compared to untreated titanium alloys. The work provides support for the suitability of hydrothermal nanosurfaces for use in corrosive environments, a significant progression toward the industrialization of the hydrothermal technique.

Relatively thick (1.2 μm), novel, flower-like nanostructured tungsten oxide thin films are obtained by electrochemically anodizing tungsten foil in a fluoride containing acidified electrolyte solution. X-ray diffraction analysis reveals the presence of monoclinic hydrated tungstite (WO3·2H2O) in the as-prepared samples, while films annealed at 400 °C for 4 h contain predominantly orthorhombic WO3phase. Scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Raman spectroscopy, and UV−vis spectroscopy are utilized to determine the surface morphology, crystal structure, and optical properties of these WO3films. An inorganic fullerene-like WO3·2H2O structure is observed, with the water molecules acting as the coordination solvent and allowing crystallographically specific growth of crystallized WO3·2H2O through oriented attachment. We propose here that the formation of the flower-like structured hydrated tungstite film occurs through an anodization/precipitation−recrystallization process. The photocurrent measurements under visible light illumination show that the flower-like structure with enhanced surface area exhibits a higher photocurrent density of 0.28 mA cm−2, compared to a photocurrent density of 0.16 mA cm−2obtained for the mesoporous structure. The possibility of controlling and adjusting the morphology by tuning the anodization conditions makes the technique an interesting candidate for fabricating photodevices over a large substrate area.

In a recent Nature Communicationspublication, Zhang et al. demonstrated a new black indium oxide photothermal catalyst capable of converting carbon dioxide to methanol under solar irradiation at ambient pressure. The catalyst shows remarkable selectivity toward methanol formation over carbon monoxide, overcoming limitations for such reactions.

While the benefit of CeO2surface oxygen vacancies for CO2methanation is well established, their role under photothermal conditions has not been probed in depth. In this work, SiO2was systematically added to suppress the influence of CeO2surface oxygen vacancies on the reaction. Overall, a decrease in CO2conversion corresponded to an increase in Si composition. However, a similar level of catalytic activity was found for Ni/Ce0.9Si0.1O2and Ni/CeO2. Unlike CeO2, Ce0.9Si0.1O2had limited surface reducibility and restricted CO2interaction, indicating a lack of surface oxygen vacancies. While the photothermal catalytic activities were found to be thermally driven and comparable to the reaction under thermal conditions, the light-driven reaction does not require external heating and promotes a sustainable approach for CO2hydrogenation. Further study by in situdiffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) suggested catalyst activity was dictated by the vacancies' proximity to the active Ni sites rather than their relative surface abundance. The findings provide new understanding on the role of CeO2oxygen vacancies in catalyst performance and catalyst design for the methanation of CO2.

Engineering the metal–carbon heterointerface has become an increasingly important route toward achieving cost-effective and high-performing electrocatalysts. The specific properties of graphene edge sites, such as the high available density of states and extended unpaired π-bonding, make it a promising candidate to tune the electronic properties of metal catalysts. However, to date, understanding and leveraging graphene edge–metal catalysts for improved electrocatalytic performance remains largely elusive. Herein, edge-rich vertical graphene (er-VG) was synthesized and used as a catalyst support for Ni–Fe hydroxides for the oxygen evolution reaction (OER). The hybrid Ni–Fe/er-VG catalyst exhibits excellent OER performance with a mass current of 4051 A g–1(at overpotential η = 300 mV) and turnover frequency (TOF) of 4.8 s–1(η = 400 mV), outperforming Ni–Fe deposited on pristine VG and other metal foam supports. Angle-dependent X-ray absorption spectroscopy shows that the edge-rich VG support can preferentially template Fe–O units with a specific valence orbital alignment interacting with the unoccupied density of states on the graphene edges. This graphene edge–metal interaction was shown to facilitate the formation of undersaturated and strained Fe-sites with high valence states, while promoting the formation of redox-activated Ni species, thus improving OER performance. These findings demonstrate rational design of the graphene edge–metal interface in electrocatalysts which can be used for various energy conversion and chemical synthesis reactions.

Metallic foams, with intrinsic catalytic properties, are critical for heterogeneous catalysis reactions and reactor designs. Market ready catalytic foams are costly and made of multimaterial coatings with large sub-millimeter open cells providing insufficient active surface area. Here we use the principle of nanometallurgy within liquid metals to prepare nanostructured catalytic metal foams using a low-cost alloy of bismuth and tin with sub-micrometer open cells. The eutectic bismuth and tin liquid metal alloy was processed into nanoparticles and blown into a tin and bismuth nanophase separated heterostructure in aqueous media at room temperature and using an indium brazing agent. The CO2electroconversion efficiency of the catalytic foam is presented with an impressive 82% conversion efficiency toward formates at high current density of −25 mA cm–2(−1.2 V vs RHE). Nanometallurgical process applied to liquid metals will lead to exciting possibilities for expanding industrial and research accessibility of catalytic foams.

Controllable concomitant production of CO and H2(syngas) during electrochemical CO2reduction reactions (CO2RR) is expected to improve the commercial feasibility of the technology to mitigate CO2emissions as the generated syngas can be converted into useful chemicals using the commercial Fischer–Tropsch (FT) process. Herein, we demonstrate the ability of a Co single-atom-decorated N-doped graphitic carbon shell-encapsulated cobalt nanoparticle electrocatalyst (referred as Co@CoNC-900) to controllably produce syngas at low overpotentials during CO2RR. Through the engineering and modulation of dual active sites for CO2RR (modified carbon shell with encapsulated Co) and hydrogen evolution reaction (Co–N4moieties) within Co@CoNC by varying the annealing temperature, we are able to tune the H2: CO ratio from 1: 2 to 1: 1 to 3: 2 over a wide range of applied potentials (−0.5 V to −0.8 V versus reversible hydrogen electrode, RHE). This versatile control of H2: CO ratio in CO2RR reaction brings up significant opportunity of using CO2and H2O and renewable energy for producing a range of chemicals.

The work describes the interactions of nanosilver (NAg) with bacterial cell envelope components at a molecular level and how this associates with the reactive oxygen species (ROS)-mediated toxicity of the nanoparticle. Major structural changes were detected in cell envelope biomolecules as a result of damages in functional moieties, such as the saccharides, amides, and phosphodiesters. NAg exposure disintegrates the glycan backbone in the major cell wall component peptidoglycan, causes complete breakdown of lipoteichoic acid, and disrupts the phosphate-amine and fatty acid groups in phosphatidylethanolamine, a membrane phospholipid. Consistent with the oxidative attacks, we propose that the observed cell envelope damages are inflicted, at least in part, by the reactive oxygen radicals being generated by the nanoparticle during its leaching process, abiotically, without cells. The cell envelope targeting, especially those on the inner membrane phospholipid, is likely to then trigger the rapid generation of lethal levels of cellular superoxide (O2•–) and hydroxyl (OH•) radicals herein seen with a model bacterium. The present study provides a better understanding of the antibacterial mechanisms of NAg, whereby ROS generation could be both the cause and consequence of the toxicity, associated with the initial cell envelope targeting by the nanoparticle.

Highlights:

A rational design of metal halide perovskites for achieving efficient CO2reduction reaction was demonstrated.

The stability of CsPbI3perovskite nanocrystal (NCs) in aqueous electrolyte was improved by compositing with reduced graphene oxide (rGO).

The CsPbI3/rGO catalyst exhibited > 92% Faradaic efficiency toward formate production with high current density which was associated with the synergistic effects between the CsPbI3NCs and rGO. Abstract: Transformation of greenhouse gas (CO2) into valuable chemicals and fuels is a promising route to address the global issues of climate change and the energy crisis. Metal halide perovskite catalysts have shown their potential in promoting CO2reduction reaction (CO2RR), however, their low phase stability has limited their application perspective. Herein, we present a reduced graphene oxide (rGO) wrapped CsPbI3perovskite nanocrystal (NC) CO2RR catalyst (CsPbI3/rGO), demonstrating enhanced stability in the aqueous electrolyte. The CsPbI3/rGO catalyst exhibited > 92% Faradaic efficiency toward formate production at a CO2RR current density of ~ 12.7 mA cm−2. Comprehensive characterizations revealed the superior performance of the CsPbI3/rGO catalyst originated from the synergistic effects between the CsPbI3NCs and rGO, i.e., rGO stabilized the α-CsPbI3phase and tuned the charge distribution, thus lowered the energy barrier for the protonation process and the formation of *HCOO intermediate, which resulted in high CO2RR selectivity toward formate. This work shows a promising strategy to rationally design robust metal halide perovskites for achieving efficient CO2RR toward valuable fuels.

Silica has the potential to enhance the performance of ceria–zirconia as a support for the dry reforming of methane; however, controlling the integration of silica with the ceria–zirconia using flame spray pyrolysis (FSP) is a significant challenge. To address this challenge, an asymmetrically variable double-FSP (DFSP) system was established to control the SiO2interaction with Ce0.7Zr0.3O2. The engineered materials were then utilized as supports for Ni for the dry reforming of methane. Initially, silica formation during FSP synthesis was examined where it was revealed that, at a low precursor concentration (<1.5 M tetraethyl orthosilicate in xylenes), the physical characteristics of the silica varied differently in relation to what is typically encountered during FSP synthesis. Explicitly, on using a 0.5 M tetraethyl orthosilicate precursor, increasing the FSP feed rate provided an increase in the specific surface area from 217 m2/g at 3 mL/min to 363 m2/g at 7 mL/min. Adopting this knowledge on silica formation under these conditions, the asymmetrical DFSP system was then exploited to regulate the integration of ceria–zirconia with the silica. To restrict the silica from coating the particles during DFSP, the intersection distance along the silica flame was tuned from 18.5 to 28.5 cm, whereas the distance along the ceria–zirconia flame was fixed at 5 cm. It was found that at short intersection distances the ceria–zirconia provided sites for silica nucleation and growth, resulting in high surface-area silica encapsulating the ceria–zirconia. At large intersection distances, encapsulation of the ceria–zirconia by silica was suppressed. An enhanced oxygen storage capacity and basicity along with the small Ni sizes facilitated by the longer intersection distances produced the most selective catalyst for the dry reforming of methane.

Optimizing interfacial contact between graphene and a semiconductor has often been proposed as essential for improving their charge interactions. Herein, we fabricated bismuth vanadate-reduced graphene oxide (BiVO4/rGO) composites with tailored interfacial contact extents and revealed their disparate behavior in photoelectrochemical (PEC) and powder suspension (PS) water oxidation systems. BiVO4/rGO with a high rGO coverage on the BiVO4surface (BiVO4/rGO HC) exhibited an 8-fold enhancement in the PEC photocurrent density with respect to neat BiVO4at 0 V versus Ag/AgCl, while BiVO4/rGO with a low rGO coverage (BiVO4/rGO LC) gave a lesser 3-fold enhancement. In contrast, BiVO4/rGO HC delivered a detrimental effect, while BiVO4/rGO LC exhibited an enhanced performance for oxygen evolution in the PS system. The phenomenon is attributed to changes in the hydrophobicity of the BiVO4/rGO composite in conjunction with the interfacial contact configuration. A better BiVO4/rGO interfacial contact was found to improve the charge separation efficiency and charge transfer ability of the composite material, explaining the superior PEC performance of BiVO4/rGO HC. Additionally, optimization of the interfacial contact extent was revealed to further improve the energetics of the composite material, as evidenced by a Fermi level shift to a more negative potential. However, the high hydrophobicity of BiVO4/rGO HC arising from the higher rGO reduction extent triggered poor water miscibility, reducing the surface wettability and therefore hampering the photocatalytic O2evolution activity of the sample. The study underlines water miscibility as a governing issue in the PS system.

Future renewable energy conversion requires advanced electrocatalysis technologies for hydrogen production, fuel cells, and metal–air batteries. Highly efficient trifunctional nonprecious electrocatalysts are a critical precious metal replacement for the economically viable electrocatalysis of oxygen reduction and water splitting, both of which are a triphase electrode process. Electrocatalysts with a refined porous structure and active composition beneficial for three-phase reactions are broadly pursued. Herein, a highly promising trifunctional spherical Murray assembly of Co–N–C nanoparticles was derived from low-cost Prussian blue analogues for the oxygen reduction reaction and water splitting. The Murray-type architecture with a tunable porous hierarchy for efficient mass transfer and the combination of a Co–N–C active composition are key for the improved electrocatalytic performance. Acid-leaching produced an optimized Murray-type durable and methanol-tolerant Co–N–C electrocatalyst that achieved an onset potential of 0.94 V [vs reversible hydrogen electrode (RHE)] and a half wave potential of 0.84 V (vs RHE) as well as a large diffusion-limited current density of 5.7 mA cm–2for the oxygen reduction reaction, which is comparable to Pt/C. In addition, it displayed low onset overpotentials of ∼150 and ∼350 mV corresponding to the hydrogen evolution reaction and oxygen evolution reaction, respectively, highlighting its great potential to be used in overall water splitting with a total splitting voltage of 1.73 V. This work highlights the importance of Murray-type electrocatalysts for multiphase energy-related reactions.

The interface at the metal oxide–carbon hybrid heterojunction is the source to the well-known “synergistic effect” in catalysis. Understanding the structure–function properties is key for designing more advanced catalyst–support systems. Using a model MnIII–Oxsingle-layer catalyst on carbon, we herein report a full elucidation to the catalytic synergism at the hybrid heterojunction in the oxygen reduction reaction (ORR). The successful fabrication of the single-layer catalyst from bottom-up is fully characterized by the X-ray absorption fine structure and high-resolution transmission electron microscopy. For oxygen electrocatalysis over this model hybrid heterostructure, our results, from both theory and experiment, show that the synergistic ORR truly undergoes a cooperated two-step electrocatalysis with catalytic promotion (ΔEonset= 60 mV) near the heterojunction and over the single-layer catalyst through an interfacial electronic interplay, rather than an abstruse transition towards a one-step dissociative pathway. Finally, we report a superior peroxide-reducing activity of 432.5 mA cm–2mg(M)–1over the MnIII–Oxsingle-layer.

Spectrum splitting for hybrid photovoltaic/thermal (PV/T) collectors presents an opportunity to deliver higher combined efficiencies than either technology alone. Nanofluids offer an inexpensive alternative to spectrum splitting mirrors, and serve both as an optical filter and a heat transfer mechanism. This paper introduces experimental testing of spectrum splitting nanofluids for three cells: c-Si, GaAs, and Ge solar cells. The nanofluids were composed of combinations of core-shell silver-silica (Ag–SiO2) nanoplates as visible light absorbers and silica-coated gold and gold-copper nanorods as infrared absorbers. These nanoparticles were suspended in various concentrations in either a water or oil base fluid according to the spectral response of the solar cell. Indoor test results are presented for all three cell types. The Ag–SiO2 aqueous fluid, paired with a c-Si PV cell, delivered the highest combined efficiency, which indicates that this PV-nanofluid combination is a strong candidate for a low cost, high-efficiency spectrum splitting technology.